The invention relates to a transmission device.
A transmission device for a motor vehicle is already known from DE 10 2011 108 024 A1, comprising a coupling unit, which for non-rotatable connection of two coupling elements has a friction-locking unit and a form-locking unit connected in parallel to the friction-locking unit, with a first hydraulic actuator for actuation of the form-locking unit, with a second hydraulic actuator for actuating the friction-locking unit and with a directional valve for controlling the first actuator.
Moreover, it is known from the generic CA 493 060 A that the directional valve has a control line connection which in at least one operational state is connected in pressure terms to the second actuator provided for actuation of the friction-locking unit.
The object of the invention is in particular to improve the control of the first actuator.
The invention relates to a transmission device for a motor vehicle, including at least one coupling unit, which for non-rotatable connection of two coupling elements has a friction-locking unit and a form-locking unit connected in parallel to the friction-locking unit, also including a first hydraulic and/or pneumatic actuator for actuation of the form-locking unit, a second hydraulic actuator for actuating the friction-locking unit and a directional valve for controlling the first actuator provided for actuation of the form-locking unit. Within the context of the invention a form-locking unit connected in parallel to the friction-locking unit is understood to be a form-locking unit connected in parallel to a form-locking unit in the flux of force. The coupling elements can be connected non-rotatably, both by closure of the friction-locking unit and also by closure of the friction-locking unit and also by closure of the friction-locking unit and the form-locking unit, to a coupling unit which, for non-rotatable connection of two coupling elements, has a friction-locking unit and a form-locking unit connected in parallel to the friction-locking unit.
Furthermore it is assumed that the directional valve has a control line connection which in at least one operational state is connected in pressure terms to the second actuator provided for actuation of the friction-locking unit. The first actuator provided for actuation of the form-locking unit can be controlled as a function of the actuation of the friction-locking unit by the connection, in pressure terms, of the control line connection of the directional valve to the second actuator provided for actuation of the friction-locking unit, so that the form-locking unit can be closed only when the friction-locking unit is closed. As a result the form-locking unit can be prevented from being closed in an unsynchronized state, so that the form-locking unit can be closed conveniently and with low wear. The first actuator provided for actuation of the form-locking unit can be controlled as a function of a disc actuation pressure provided for actuation of the parallel connected friction-locking unit, so that a reliable criterion can be provided particularly simply for closure of the form-locking unit. As a result a convenient and low-wear closure of the form-locking unit can take place reliably, so that the control of the first actuator provided for actuation of the form-locking unit can be improved. A “coupling unit” should also be understood in particular to be both a clutch and also a brake. A “clutch” should be understood in particular to be a unit which is provided in order for two rotatably disposed coupling elements to be selectively connected to one another non-rotatably or separated from one another. A “brake” should be understood in particular to be a unit which is provided in order for a rotatable coupling element and a fixed coupling element, which is preferably connected non-rotatably to a fixed component or is formed integrally therewith, to be selectively connected to one another non-rotatably or separated from one another. The fixed component is advantageously configured as a transmission housing for the transmission device. A “friction-locking unit” should be understood in particular to be a unit which produces the non-rotatable connection substantially by a frictional grip produces, such as for example a multiple-disc clutch or a multiple-disc brake. A “form-locking unit” should be understood in particular to be a unit which produces the non-rotatable connection substantially by form locking, such as for example a claw clutch or a claw brake. The friction-locking unit and the form-locking unit are preferably functionally disposed between the two coupling elements. A “control line connection” should be understood in particular to be a hydraulic or pneumatic operating material connection which is provided for switching of the directional valve and/or is connected in pressure terms to a control volume of the directional valve for supply of operating medium pressure to the control volume. Within the context of the invention a control volume should preferably be understood as a volume which is delimited by a valve housing of the directional valve and a control surface of a valve slide, which is movable in the valve housing, of the directional valve. An operating medium pressure prevailing in the control volume preferably acts on the control surface of the valve slide which delimits the control volume, so that the valve slide shifts in the valve housing in the event of corresponding supply of operating medium pressure. A “connection in pressure terms” should be understood in particular to be a hydraulic or pneumatic connection between at least two connection partners by which at least in a hydrostatic operational state an at least substantially equal operating medium pressure prevails on, in and/or between the connection partners. “Provided” should be understood in particular to mean specially constructed, equipped, configured and/or disposed. The control line connection according to the invention, which in at least one operational state is connected in pressure terms to the second actuator provided for actuation of the friction-locking unit, is provided so that the control volume connected in pressure terms to the control line connection can be supplied with the disc actuation pressure. The disc actuation pressure acts on the control surface delimiting the control volume for the disc actuation pressure of the valve slide of the directional valve.
According to the invention it is proposed that the directional valve has a second control line connection which in at least one operational state is connected in pressure terms to the first actuator provided for actuation of the form-locking unit. As a result a claw actuation pressure for actuation of the form-locking unit and the disc actuation pressure provided for actuation of the parallel connected friction-locking unit can be used to control the directional valve, so that the control of the first actuator can be optimized. The control line connections of the directional valve are preferably associated in each case with a control volume, and are provided for the supply of operating medium pressure in each case to a control volume, wherein the control volumes are separated from one another in pressure terms. The second control line connection according to the invention, which in at least one operational state is connected in pressure terms to the first actuator provided for actuation of the form-locking unit, is provided so that the control volume connected in pressure terms to the second control line connection can be supplied with the claw actuation pressure. The claw actuation pressure acts on the control surface of the valve slide of the directional valve, which control surface delimits the control volume which is connected in pressure terms to the second control line connection.
In a further embodiment of the invention it is advantageous if the directional valve has a valve slide with two control surfaces associated in each case with one of the control line connections, wherein the control surfaces are oriented in the same direction. As a result, with the form-locking unit closed, a valve position of the directional valve which is set by the disc actuation pressure provided for actuation of the friction-locking unit can be maintained by the claw actuation pressure provided for actuation of the form-locking unit, and the disc actuation pressure can be lowered, for example for releasing a tooth-on-tooth position in the form-locking unit, without the directional valve leaving the valve position set by the disc actuation pressure. As a result advantageously it is also possible in principle for the claw actuation pressure to be used for maintaining the valve position set by the disc actuation pressure, so that the friction-locking unit can be opened after the closure of the form-locking unit. A “control surface associated with a control line connection” should be understood in particular to be a control surface which delimits a control volume which is connected in pressure terms to the control line connection for the supply of operating medium pressure, so that preferably an operating medium pressure applied to the control line connection prevails in the control volume and thus acts on the control surface. “Control surfaces which are oriented in the same direction” should in particular be understood to mean that surface normals of one control surface and surface normals of the other control surface are aligned in the same direction. Under the action of an operating medium pressure the control surfaces oriented in the same direction are preferably provided for movement of the valve slide for an adjustment of the same valve position of the directional valve. A supply of operating medium pressure to control volumes associated with control surfaces which are oriented in the same direction effects a movement of the valve slide in the same direction. A “surface normal” should in particular be understood to be a direction vector which is disposed orthogonally on a surface and directed away therefrom.
In a further embodiment of the invention the directional valve has at least one third control line connection and the valve slide has a control surface which is associated with the third control line connection and is oriented in the opposite direction to the further control surfaces of the valve slide. Due to the third control line connection which is additionally provided in this embodiment of the invention with the control surface associated with the third control line connection, the valve slide of the directional valve can advantageously be supplied with an additional third control pressure and the valve position can be set as a function of the third control pressure. In particular in a transmission device having a further coupling unit which is likewise controlled by the directional valve, in the event of gear shifts, due to the possible supply of a third control pressure to the valve slide of the directional valve conflicts for the control of the further coupling unit by the directional valve can be avoided, so that particularly convenient gear shifts can be performed. Within the context of the invention the further coupling unit which is likewise controlled by the directional valve is designated as a second further coupling unit. Due to the possible supply of a third control pressure to the valve slide of the directional valve, conflicts for the control of the second further coupling unit in the event of a gear shift from an actual gear, in which the coupling unit is closed, into a target gear, in which the second further coupling unit is closed, can be avoided. Furthermore a spring of the directional valve can be supported by a supply of operating medium pressure to the third control surface via the third control line connection, so that the spring can advantageously be configured for low spring forces. A control surface “which is oriented in the opposite direction to the further control surfaces” should be understood in particular to mean that surface normals of the control surface and surface normals of the further control surfaces are aligned in opposite directions to one another. Under the action of an operating medium pressure the control surfaces oriented in opposite directions are preferably provided for movement of the valve slide for setting of opposing valve positions of the directional valve.
In a further embodiment of the invention the transmission device has a solenoid valve and a third actuator for actuation of a first further coupling unit, wherein in at least one operational state the first further coupling unit is connected in pressure terms to the third control line connection, so that an operating medium pressure provided for actuation of the third coupling unit can be used as third control pressure for an adjustment of the directional valve. Within the context of the invention the fact that a “solenoid valve has an . . . actuator for actuation of a . . . coupling unit” is understood to mean that a solenoid valve controls an actuator and the actuator then actuates the coupling unit by the solenoid valve according to the control guidelines. The provision of the third control line connection, which is connected in pressure terms to the third actuator for actuation of the first further coupling unit, advantageously enables an adjustability of a supply of operating medium pressure to the third control line connection by means of the solenoid valve, which is provided for an operating medium pressure adjustment in the third actuator for actuation of a first further coupling unit of the transmission device. Thus the operating medium pressure set by the solenoid valve can be used advantageously not only for actuation of the first further coupling unit, but additionally also for control of the form-locking unit. According to the invention the disc actuation pressure provided for actuation of the friction-locking unit acts on the valve slide of the directional valve as a control pressure, the claw actuation pressure provided for actuation of the form-locking unit acts as a second control pressure, and the operating medium pressure provided for actuation of the first further coupling unit acts as a third control pressure. In this case the directional valve according to the invention is configured so that on the valve slide of the directional valve the operating medium pressure provided for actuation of the first further coupling unit counteracts the claw actuation pressure provided for actuation of the form-locking unit and the disc actuation pressure provided for actuation of the parallel connected friction-locking unit.
In a further embodiment according to the invention the directional valve has at least one spring of which the spring force is oriented in the same direction as the control surface which is associated with the third control line connection of the valve slide. If in the transmission device according to the invention the solenoid valve and the third actuator are provided for actuation of the first further coupling unit, wherein in at least one operational state the first further coupling unit is connected in pressure terms to the third control line connection, and the operating medium pressure provided for actuation of the first further coupling unit and the spring force counteract the claw actuation pressure provided for actuation of the form-locking unit and the disc actuation pressure provided for actuation of the parallel connected friction-locking unit, then advantageously the extent of transverse influences on the further control system of the transmission device which originate from a control of the directional valve can be kept small, which is explained in greater detail for an exemplary embodiment of the invention.
In a further embodiment of the invention the first further coupling unit is closed in a fourth, fifth, sixth, seventh, eighth and ninth forward gear and the coupling unit is closed in the eighth forward gear, in the ninth forward gear and in a reverse gear. If in the transmission device according to this embodiment of the invention the solenoid valve and the third actuator are provided for actuation of the first further coupling unit, wherein in at least one operational state the first further coupling unit is connected in pressure terms to the third control line connection, and the operating medium pressure provided for actuation of the first further coupling unit and the spring force counteract the claw actuation pressure provided for actuation of the form-locking unit and the disc actuation pressure provided for actuation of the parallel connected friction-locking unit, then advantageously control of the form-locking unit by the directional valve according to the invention in the reverse gear is simple in control engineering terms. In the transmission device according to this embodiment of the invention, in the reverse gear the control volume of the directional valve, which is delimited by the control surface associated with the third control line connection, is without pressure.
In a further embodiment of the invention the transmission device has a working pressure system which, in at least one operational state, is connected in pressure terms to the third control line connection. As a result the directional valve can be switched as a function of the working pressure, so that the first actuator provided for actuation of the form-locking unit can be controlled as a function of the working pressure, the disc actuation pressure and the claw actuation pressure. Thus according to the invention the disc actuation pressure provided for actuation of the friction-locking unit acts as a control pressure, the claw actuation pressure provided for actuation of the form-locking unit acts as a second control pressure, and the operating medium pressure acts as a third control pressure. In this case the working pressure advantageously counteracts the claw actuation pressure provided for actuation of the form-locking unit and the disc actuation pressure provided for actuation of the parallel connected friction-locking unit. Within the context of the invention the working pressure system is understood to be the operating medium pressure system for the transmission device, which system is provided for control of the coupling units of the transmission device. In this case the level of the working pressure of the working pressure system is configured with the pressure which is necessary for keeping the coupling units closed in the event of maximum torque requirements.
Furthermore it is proposed that the directional valve has at least one spring of which the spring force is oriented in the opposite direction to the control surface of the valve slide which is associated with the third control line connection. In particular as a result the spring can support the disc actuation pressure provided for actuation of the friction-locking unit and/or the claw actuation pressure provided for actuation of the form-locking unit for movement of the valve slide against the working pressure, so that it is possible that the spring switches the directional valve into a selected valve position when the disc actuation pressure and/or the claw actuation pressure is equal to the working pressure. The control surface and the spring of which the spring force is opposed, with regard to the switching direction, to the control surface associated with the third control line connection are preferably provided for movement of the valve slide in opposite directions. The spring of which the spring force is opposed, with regard to the switching direction, to the control surface associated with the third control line connection, and the operating medium pressure acting on the control surface, act for movement of the valve slide preferably into opposing valve positions. Thus according to the invention the working pressure counteracts the claw actuation pressure provided for actuation of the form-locking unit, the disc actuation pressure provided for actuation of the parallel connected friction-locking unit, and the spring force.
Furthermore it is proposed that the transmission device has a further solenoid valve and a fourth actuator for actuation a second further coupling unit, wherein the directional valve has a first working line connection to which the first actuator is connected, and a second working line connection to which the fourth actuator is connected. As a result the further solenoid valve can be used both for actuation of the form-locking unit and also for actuation of the second further coupling unit, so that the number of solenoid valves and thus the complexity in the transmission device can be kept low. A “working line connection” should be understood in particular to be a hydraulic or pneumatic connection which is provided for supplying operating medium to at least one component of the transmission device or of the motor vehicle, in particular a coupling unit of the transmission device, preferably in order to actuate it, to cool it and/or to lubricate it.
In this embodiment of the invention an adjusted valve position of the directional valve, in which the further solenoid valve is connected to the first actuator for actuation of the form-locking unit, can be maintained only with the claw actuation pressure provided for actuation of the form-locking unit, so that the disc actuation pressure can be lowered, for example for releasing a tooth-on-tooth position of the form-locking unit, without the directional valve leaving the set valve position. Thus a tooth-on-tooth-position of the form-locking unit can advantageously also be released in this embodiment of the invention.
In a further embodiment of the invention the transmission device has a switch-over valve which is provided in order for the control line connection provided for connection to the second actuator to be connected in pressure terms to the first actuator. The provision on the valve slide of a control surface which is only associated with the second control line connection can advantageously be avoided by the provision of the switch-over valve, so that a constructively simple directional valve which is cost-effective in terms of production technology can be provided without a stepped valve slide.
When only one control line connection is provided for the first actuator and the second actuator it is also basically possible for the claw actuation pressure to be used for maintaining the valve position set by the disc actuation pressure, so that the friction-locking unit can be opened after the closure of the form-locking unit.
Further advantages can be seen from the following description of the drawings. Three exemplary embodiments of the invention are shown in the drawings. The drawings, the description of the drawings and the claims contain numerous features in combination. Expediently, the person skilled in the art will also consider the features singly and combine them to form meaningful further combinations.